The present invention relates to the skin disease known as psoriasis and, more particularly, to compositions and methods for the treatment of psoriasis.
Psoriasis is a chronic, recurrent, scaling skin disease of unknown etiology. Erythematous eruptions, often in papules or plaques, and usually having a white, silvery scale, can affect any part of the skin, but most commonly affect the scalp, the extensor surfaces of the elbows and knees, and the lower portion of the back. The disease usually occurs in adults, but children may also be affected. Over one million people in the United States have the discomfort and disfigurement of psoriasis, and of these more than 11% have experienced disability of such severity as to compromise employment and effectiveness. Patients with psoriasis have a much greater incidence of arthritis, and generalized exfoliation and even death can threaten afflicted individuals.
Psoriasis is without cure, and the course and remission of the disease are unpredictable, even capricious. Current therapeutic regimens include topical or intralesional application of corticosteroids, topical administration of anthralin or keratolytics, and use of tar and UV light on affected areas. These many treatments all have their benefits and drawbacks, and many factors must be considered in the choice of therapy. No single therapy is ideal, and it is rare for a patient not to be treated with several alternatives during the relapsing and remitting course of the disease. Whereas systematic treatment can induce prompt resolution of psoriatic lesions, suppression often requires ever-increasing doses, sometimes with toxic side effects, and tapering of therapy may result in rebound phenomena with extensions of lesions, possibly to exfoliation.
Information representing the current state of the art with respect to psoriasis and its treatment can be found in, e.g., Lowe, Nicholas J., Practical Psoriasis Therapy, Year Book Medical Publishers, Chicago, 1986, pp. 11-13; Mier, Paul D., and van de Kerhof, Peter C. M., eds., Textbook of Psoriasis, Churchill Livingstone, New York, 1986, pp. 13-39, 167 et seq; and Wyngaarden, James B., and Smith, Lloyd H., Cecil's Textbook of Medicine, W. B. Saunders Co., Philadelphia, 1988, pp. 2326-2327.
The primary object of this invention is to provide a treatment for psoriasis, and more particularly, to provide a therapy based upon topical application to affected skin areas of an active agent or precursor thereof, preferably in association with a dermatologically acceptable carrier or vehicle.